<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .myStyle {
            background-color: antiquewhite;
        }
    </style>
</head>
<body>
<button id="btn">点我创建一个输入框</button>
<script>
    const btn = document.getElementById('btn');
    btn.onclick = () => {
        const input = document.createElement('input')

        input.className = "myStyle"
        input.value = '100'
        input.onclick = () => {
            alert('1')
        }
        document.body.appendChild(input)
        input.focus()
    }
</script>
</body>
</html>
